Final answer:
The enthalpy reading on a psychrometric chart indicates the total heat content of a pound of air.
Step-by-step explanation:
The reading on a psychrometric chart that shows the total heat content of a pound of air is indicated by the enthalpy. Enthalpy is a measure of heat energy in a thermodynamic system and is expressed in terms of energy per mass, such as BTU per pound in the English system or joules per kilogram in the metric system. The psychrometric chart is a graphical representation of the physical and thermal properties of moist air, which are used in air-conditioning and refrigeration calculations.